Current memory technologies, including DRAM (dynamic random access memory), SRAM (static RAM) and NAND Flash, are quickly approaching their scalability limits. Accordingly, there is a strong need for new memory technologies that can meet the performance requirements of future memory applications. Resistive RAM, which is a type of memristor, is a promising technology and has been shown to exhibit great scalability, non-volatility, multiple-state operation, 3D stackability, and CMOS compatibility. There have been, however, challenges in improving the performance of such devices, such as device endurance, thermal stability, and switching speed.